The present invention relates emulsifiers for highly saturated, hydrocracked and/or hydroisomerized fluids. More particularly, the present invention relates to compositions containing emulsified, highly saturated hydrocracked and/or hydroisomerized oils particular useful when applied to crops.
Petroleum oils have long been sprayed on agricultural crops as a means of pest control. Properly processed petroleum oils are generally less phytotoxic than many synthetic pesticides, with the resulting oil cover affecting the target mites, flies, bugs, scales, aphids and the like but having little deleterious effect on the target tree, plant or crop.
Conventional spray oils are manufactured from crude oil and petroleum fractions using conventional solvent refining techniques or using hydro-treated base oils. Typically, the higher the paraffinic content (i.e., the proportion of saturated straight or branched hydrocarbon chains) in the oil, the more effective the oil is against pests and the less phytotoxic it is to plants. Oils containing high normal paraffinic contents can lead to an elevated pour temperature, which can cause problems when the oil is applied as a spray oil in colder climates.
Finished spray oils typically include 1 to 3 weight percent (wt %) of an emulsifier to allow the oil to remain emulsified in a water carrier during spraying. Conventional emulsifiers for this purpose include alkyl phenol ethoxylates.
Although such alkyl phenol ethoxylates perform satisfactorily under most conditions, their emulsification capability decreases substantially under hard water conditions. When conventional spray oils emulsified with alkyl phenol ethoxylates and hard water, separation can occur during or shortly after spraying, in which case the non-emulsified oil or other composition constituents separate out on the plant leaf, causing phytotoxicity which may be evidenced by leaf browning.
Severely hydrocracked and/or severely hydrocracked hydroisomerized oils, having a saturate content of xe2x89xa799% and/or exhibiting a high degree of branching of the paraffin molecules, are now available. Exemplary severely hydrocracked and hydroisomerized oils include the Spray Oil 10, Spray Oil 13, Spray Oil 15 and Spray Oil 22 hydrocracked and hyroisomerized oils available from Petro-Canada Lubricants of Mississauga, Ontario L5K 1A8, Canada, characteristics of which are summarized below:
The hydrotreating or hydrocracking step can be carried out in the presence of a catalyst based group VIB and VII metals, or alternatively, in the presence of a catalyst based on a crystalline silicoaluminophosphate molecular sieve. Typical hydrocracking or hydrotreating conditions include temperatures of from 200 to 450xc2x0 C., hydrogen pressures of from 400 to 5,000 psig, a hydrogen circulation rate of 400 to 15,000 SCF/B and space velocities of from 0.1 to 20 hr-1. Hydroisomerization is typically carried out after the hydrocracking or hydrotreating step using a crystalline silicoaluminophosphate molecular sieve catalyst, which optionally contains group VII and IIA metals. The process is carried out at a temperature of from 250 to 450xc2x0 C., at hydrogen pressures of from 100 to 5000 psig, a hydrogen circulation rate of 400 to 15,000 SCF/B and liquid hourly space velocity of 0.1 to 20 hr-1.The hydroisomerized fluid is hydrofinished at temperatures of from 190 to 340xc2x0 C. and pressures of from 400 to 500 psig, a hydrogen circulation rate of 400 to 15,000 SCF/B, in the presence of a solid metal hydrogenation catalyst. The initial hydrotreating or hydrocracking step can be carried out in the presence of a catalyst based group VIB and VIII metals, or alternatively, in the presence of a catalyst based on a crystalline silicoaluminophosphate molecular sieve. Typical hydrocracking or hydrotreating conditions include temperatures of from 200 to 450xc2x0 C., hydrogen pressures of from 400 to 5,000 psig, a hydrogen circulation rate of 400 to 15,000 SCF/B and space velocities of from 0.1 to 20 hr-1. Typically, the finished product has a natural pour point of from xe2x88x9230 to xe2x88x9260xc2x0 C., and below, with a preferred pour point of below xe2x88x9250xc2x0 C.
While the above techniques are used to produce severely hydrocracked and hydroisomerized fluids, issues of adequate emulsification performance under hard water conditions present with such fluids can also be present with fluids which are not hydroisomerized but are hydrocracked or obtained through solvent extraction and contain 80-95 wt % or more saturates. As used herein the phrase hydrocracked and/or hydroisomerized fluids includes organic fluids which are either hydrocracked or hydroisomerized or both and contain a saturate content of  greater than 80%. Examples of such fluids available from suppliers other than Petro-Canada are described below:
Unfortunately, hydrocracked and/or hydroisomerized fluids are not readily usable as spray oils because they are often less soluble then conventional oils. As a result of this poorer solubility, the otherwise conventional alkyl phenol emulsifiers tend to drop out of solution upon standing. Conventionally used emulsifiers do not seem to perform adequately and do not have the required storage stability when added to hydrocracking and/or hydroisomerized oils.
The emulsification capability of a potential emulsifier may be evaluated by considering its hydrophile/lipophile balance (hereinafter HLB value). The HLB value, which is an approximate measure of polarity, usually ranges from 2-18. The higher the number, the more polar the subject moleculexe2x80x94the lower the number, the less polar the subject molecule. The more polar molecules are generally more soluble in water and the less polar molecules generally more soluble in oil. However, in evaluating potential emulsifiers for use with hydroisomerized fluids, the HLB values have proven to have poor predictive value, with no single emulsifier performing satisfactorily.
Below is a list of commercially available emulsifiers, which were tested for emulsification ability with hydrocracking and hydroisomerized fluids, including emulsifier class, source, product name, HLB value, average number of ethoxylate or alcohol groups per molecule, and carbon chain numbers, if known.
None of these emulsifiers alone provided satisfactory emulsification with Spray Oil 22 and Spray Oil 10 hydrocracked and hydroisomerized fluids.
It can be see there remains a continuing need for an emulsifier that can emulsify hydrocracked and/or hydroisomerized fluids. There remains a further need for such an emulsifier for use with hydrocracked and/or hydroisomerized fluids, which will result in an emulsified product which is satisfactory for use in agricultural applications as a spray oil. In addition, there remains a need for an emulsifier adaptable for use with conventional spray oils as well as hydroisomerized spray oils, that will maintain emulsification ability when solubilized in hard water, so as to minimize phytotoxicity to the plants to which such spray oils are applied. It is against this background that the techniques of the present invention have been developed.
The emulsifier blends of the present invention include ethoxylated alcohols containing C10-C16 carbon chains having on average 2.8 or more ethoxy or alcohol groups per carbon chain together with glycerol mono-, di- and/or trioleates. A preferred emulsifier blend of the present invention contains ethoxylated alcohol:glycol mono- and/or dioleates in a ratio of wt % of from 9:1 to 4:6. Said another way, a preferred emulsifier blend of the present invention contains from 90% to 40% by weight of ethoxylated alcohols and 10% to 60% of a mixture of glycol mono and/or dioleates. A more preferred emulsifier blend contains C12-C16 carbon chains and contains ethoxylated alcohols and glycerol mono- and/or dioleates in a ratio of 9:1 to about 6:4. A most preferred ratio of ethoxylated alcohols and glycerol mono- and/or dioleates is 4:1.
The emulsifier blends of the present invention find particular utility in the emulsification of hydrocracked and/or hydroisomerized fluids, especially oils, which may then be employed as spray oils for subsequent application to agricultural crops. The emulsifier blends of the present invention are also very useful in emulsifying conventional spray oils in hard water, prior to application to agricultural crops.
The emulsifier blends of the present invention include ethoxylated alcohols containing C10-C16 carbon chains having on average at 2.8 or more ethoxy or alcohol groups per carbon chain together with glycerol mono- and/or dioleates. A preferred emulsifier blend of the present invention contains ethoxylated alcohol:glycol mono- and/or dioleates in a ratio of wt % of from 9:1 to 4:6. Said another way, a preferred emulsifier blend of the present invention contains from 90% to 40% by weight of ethoxylated alcohols and 10% to 60% of a mixture of glycol mono and/or dioleates. A more preferred emulsifer blend contains C12-C16 carbon chains and contains ethoxylated alcohols and glycerol mono- and/or dioleates in a ratio of 9:1 to about 6:4. A most preferred ratio of ethoxylated alcohols and glycerol mono- and/or dioleates is 4:1.
The process of evaluating and identifying a preferred ethoxylated alcohol/glycerol dioleate composition is further described below in Example I.